CODEWITHSUNDEEP
javascriptasp.netcollections
Ram Singh
Ram Singh

Reputation: 6928

how to add dynamic items in a collection in javascript?

i want to add number of elements in a collection in javascript,as doing in following vb's code

    Dim myList As New List(Of String)


    Dim i As Integer
    For i = 0 To rep_UnAssignComps.Items.Count
        myList.Add(i)
    Next

I want to compare this collection with a particular value.provide me syntax for comparing the value also. like

myList.Contains(val1)

Upvotes: 2

Views: 15253

Answers (3)

VinayC
VinayC

Reputation: 49215

Not sure what you want to store in the collection but in java-script, you have two choices to achieve collections.

First is to use arrays. For example,

var arr = [];  // empty array
arr.push('A');
arr.push('B');
arr.push('C');
alert(arr.length); // alerts 3
alert(arr[1]);     // alerts B (zero based indexing)

To check if any element exists or not, you have to run a loop over an array comparing element at each index.

Another method will be using java-script object as hash table. Essentially, every java-script object can have multiple properties that are essentially name-value pairs. For example,

var o = { } // empty object
o["prop1"] = "A";   // Added property named prop1 with value "A"
o["prop2"] = "B";   // Added property named prop2 with value "B"
o["prop3"] = "C";   // Added property named prop2 with value "C"
alert(o["prop1"]);  // alerts A
alert(o.prop2);     // alerts B - notice alternate syntax
alert(o["prop4"]);     // alerts undefined - because we are accessing non-existent property
if (o["prop3"]) {
  alert("prop3 exists");  // to check for some property
}
for (p in o) {  // iterate all properties
  alert(p);     // alerts property name
  alert(o[p]);  // alerts property value
}

Upvotes: 10

U.Ahmad
U.Ahmad

Reputation: 618

var myList = []
var i = 0;

if "rep_UnAssignComps" is an array use for loop else use for in

if (rep_UnAssignComps instanceof Array) {
    for (i = 0; i < rep_UnAssignComps.length; i++){
       myList.push(i);
    }
}else {
    for(var name in rep_UnAssignComps){
        if (rep_UnAssignComps.hasOwnProperty(name)){
            myList.push(i);
            i++;
        }
    }
}

To compare use:

//Returns the first index at which a given element can be found in the array, or -1 if it is not present
myList.indexOf(val1);

Upvotes: 0

Artem Koshelev
Artem Koshelev

Reputation: 10604

Use push method http://www.w3schools.com/jsref/jsref_push.asp

Upvotes: 0

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